In general, x-ray light source refers to a device generating x-ray which is usually composed of x-ray tube, power supply and control system, auxiliary apparatus for cooling and shielding etc. or the like. The core of the device is the x-ray tube. The X-ray tube usually consists of cathode, anode, glass or ceramic housing etc. The cathode is a directly-heated spiral tungsten filament. When in operation, it is heated to a high-temperature state by current, thus generating thermal-transmitted electronic beam current. The cathode is surrounded by a metal cover having a slit in the front end thereof and focusing the electrons. The anode is a tungsten target inlayed in the end surface of the copper billet. When in operation, a high pressure is applied between the cathode and anode. The electrons generated by the cathode move towards the anode under the effect of electric field and ram the surface of the target, thereby the x-ray is generated.
X-ray presents a wide range of applications in the fields of nondestructive detection, security check and medical diagnoses and treatment etc. In particular, the x-ray fluoroscopic imaging device utilizing the high penetrability of the x-ray plays a vital role in every aspect of people's daily lives. The early device of this type is a film flat fluoroscopic imaging device. Currently, the advanced technology is digital, multiple visual angles and high resolution stereoscopic imaging device, e.g. CT (computed tomography), being able to obtain three-dimensional graphs or slice image of high definition, which is an advanced application.
In the current CT device, the x-ray source and the detector need to move on the slip ring. In order to increase the speed of inspection, the moving speeds of x-ray source and the detector are normally high leading to a decreased overall reliability and stabilization. In addition, due to the limit of moving speed, the inspection speed of the CT is limited accordingly. Therefore, there is a need for the x-ray source generating multiple visual angles without displacing.
To address the problems of reliability, stabilization and inspection speed caused by the slip ring as well as the heat resistance problem of the anode target spot, there are methods provided in the available patent literature. For example, rotating target x-ray source can solve the overheat of the anode target to some extent. However, its structure is complex and the target spot generating x-ray is still a definite target spot position with respect to the overall x-ray source. For instance, in some technology, a plurality of dependent conventional x-ray sources are arranged closely in a periphery to replace the movement of x-ray source in order to realize multiple visual angles of a fixed x-ray source. Although multiple visual angles can be realized, the cost is high. In addition, the space between the target spots of different visual angles is big and the imaging quality (stereoscopic resolution) is quite poor. What's more, a light source generating distributed x-ray and the method thereof is disclosed in the patent literature 1 (U.S. Pat. No. 4,926,452), wherein the anode target has a large area remitting the overheat of the target and multiple visual angles could be produced since the position of target spot changes along the periphery. Although the patent literature 1 performs scanning deflection to the accelerated high-energy electron beam, there are still problems of difficult control, non-disjunction of target spots and poor repeatability. Anyway, it is still an effective way to generate distributed light sources. Moreover, the light sources generating distributed x-ray and methods thereof are proposed in the patent literature 2 (US20110075802) and patent literature 3 (WO2011/119629), wherein the anode target has a large area remitting the overheat of the target and multiple visual angles could be produced since the position of target spots are fixed dispersedly and are arranged in an array. In addition, CNTs (carbon nano tubes) are employed as cold cathodes and the cold cathodes are arranged in an array. The transmitting is controlled by utilizing the voltage between cathode and grid so as to control each cathode to emit electron in sequence and bombard the target spot on the anode in an order correspondingly, thus becoming the distributed x-ray source. However, there are disadvantages of complex manufacturing process and poor transmitting capability and short lifetime of carbon nano tubes.